How To Remove A Stuck Blade Bolt On A Lawn Mower?

Keeping a lawn healthy is more than simply mowing regularly. Without proper care and maintenance, your lawn mower’s blades can become dull and cause damage to the grass you’re trying to keep lush and beautiful.

To prevent this from happening, it’s essential to check for regular wear-and-tear items such as loose or missing nuts and bolts, broken or cracked blades, worn spark plugs, etc.

One common issue that may arise is having difficulty with a blade bolt getting stuck in the engine block of your mower. Luckily there are ways you can avoid this situation altogether.

In today’s post, we will explore some tips on properly maintaining your lawn mower so the blade bolt doesn’t get stuck. Keep reading to find out more.

Why Does A Lawn Mower Blade Bolt Get Stuck?  

There are some causes why your lawn mower blade bolt is so hard to loosen, like:

  • Overtightened bolt- The mower blades should not be bolted too tightly; flexibility and looseness are necessary to allow the blade to slip when it strikes a solid object while mowing. Not only does an overly tight bolt cause issues with operating the mower, but it also makes it difficult to remove the blade. It is essential to have enough play for optimal performance and protection.
  • Rusty bolt- Rust can accumulate on the blade bolt, making it harder to loosen. The rust can grind against itself, making turning the bolt difficult.
  • Old and worn-out bolts- When a mower gets old, parts rust over time. This corrosion makes it more challenging to loosen and remove the blade bolt.
  • Bolt threaded in the incorrect direction- When the bolts are not installed correctly, it is difficult to unscrew them as they will most likely be stuck.

Tools and Safety Equipment

Before we begin, make sure you have the following items on hand:

  1. Properly fitting work gloves
  2. Safety goggles
  3. Socket wrench (with the appropriate sized socket)
  4. Breaker bar (also known as a cheater bar)
  5. Penetrating oil (e.g., WD-40 or similar)
  6. Wire brush

Inspecting the Issue of Lawn Mower Blade Bolt Stuck

Before attempting to remove the stuck bolt, it’s essential to understand why the bolt may be stuck in the first place. There are a few possible reasons:

  1. Rust or corrosion
  2. Over-tightening
  3. Cross-threading

Take a close look at the bolt, and if you notice any signs of corrosion or rust, use the wire brush to clean the area as much as possible. This will help make the removal process more accessible.

How To Remove A Stuck Mower Blade Bolt?

The following section will discuss the different methods for removing a stuck blade bolt.

Preparations For Lawnmower Blade Bolt Stuck Issue

  • Disconnect the spark plug wire: This is an essential safety step to ensure that the mower doesn’t accidentally start while you’re working on it.
  • Tip the mower on its side: Carefully tilt it so it rests with the carburetor facing up. This will prevent fuel from leaking into the engine, causing damage.
  • Apply penetrating oil: Generously spray the penetrating oil onto the stuck blade bolt and let it sit for 15-20 minutes. This will help to loosen the bolt by breaking down rust and corrosion.

Method 1: Removing Stuck Blade Bolt Form Lawn Mower

After preparing, you can review the options to remove the bolt.

Method 2: Use An Impact Wrench

This should be a quick fix if you are the fortunate owner of an impact wrench. Make sure that the bolt is not stripped before beginning, though! Fasten on a compatible adapter, and you’re good to go. You’ll need other tactics if your impact driver’s power isn’t up to the task.

Method 3: Use A Socket Wrench And Extension Bar

The most accessible option is to use a socket wrench. If you don’t have one, a regular twist will do. Secure the blade with a wooden block between it and the cutting deck so that the blade doesn’t turn when you apply tension on the wrench, the edge doesn’t turn. Note that most blade bolts have right-handed threads, so turning it anti-clockwise will release it from its bindings. To generate more leverage than just a handle, use a breaker bar or an extended piece of steel pipe fitted onto the wrench handle.

Method 4: Use A Vice Grip

If the bolt has been slightly stripped or if there’s no pipe available for leverage, a vice grip is your go-to. Fasten the vice grip onto the bolt as securely as you can. Employ a hammer – preferably a rubber mallet – to tap on the end of the vice grip and rotate it in an anti-clockwise direction to loosen it. Once that’s done, you may switch back to a socket wrench.

Method 5: Use A Hammer And Chisel

If even the vice grip doesn’t work and there’s severe stripping on the bolt head, try using a hammer and chisel. Place the chisel on top of the bolt – left corner if viewed from the front for an anti-clockwise turn – hold it in place and gently tap with the hammer until it digs into the bolt enough to loosen.

Method 6: Weld An Additional Bolt

If the blade bolt is too stripped and the chiseling doesn’t work, your last resort is to weld an additional bolt onto it. This will provide a non-stripped head that you can grip onto. However, ensure welding is done correctly – you don’t want the new bolt breaking off or accidentally taking the blade.

Additional Heat-up technique: If all else fails, you can use a heat-up approach to loosen the bolt. Heat the blade with a blow torch or other appropriate heating tool, but do not overheat it. This method effectively reduces rusted and corroded bolts as the extreme temperature causes them to expand and contract, making it easier to unscrew them.

Tips for Damage Avoidance

To ensure a safe and damage-free process, keep the following tips in mind:

  1. Always wear work gloves and goggles for proper safety.
  2. Be patient and allow the penetrating oil to work before applying force.
  3. Maintain a firm grip on the mower blade and breaker bar to avoid slips and accidents.
  4. Stick to steady, controlled movements when loosening the bolt.

Prevention and Maintenance

To keep your lawn mower in good condition and prevent future stuck blade bolts, follow these maintenance tips:

  1. Regularly clean the underside of your mower to reduce the likelihood of rust formation.
  2. Apply a thin layer of anti-seize lubricant to the threads of the blade bolt when reinstalling to prevent future issues.
  3. Avoid over-tightening the blade bolt, as this can cause it to become stuck.
  4. Perform regular

Frequently Asked Question

Are lawn mower blade bolts reverse thread?

Mower blades must be secured in place with bolts that are correctly tightened to the manufacturer’s specifications.

Unfortunately, these bolts are often overly tightened due to an abundance of caution, and corrosion may make them difficult to remove.

Some large walk-behind mowers and certain lawn tractors feature one left-handed thread blade bolt; the other bolt is a standard right-hand thread.

What size socket do I need for a lawn mower blade?

15/16″ wrench is generally used to remove a lawnmower blade, though it may depend on the model. Refer to the user manual to find out what wrench size you need for your mower.

How do I loosen a rusted lawn mower blade?

The best way to loosen a rusted lawn mower blade is to use a penetrating oil such as WD-40. Spray the oil directly onto the blade bolt and let it sit for 15-20 minutes before attempting to loosen it. You may also use a wire brush to remove any rust or corrosion that may be present on the bolt.


Stuck lawn mower blade bolts can be difficult to remove, but it can be done with the right tools and techniques. Use safety precautions when removing a stuck bolt, such as disconnecting the spark plug wire and tipping the mower on its side.

You may need to use an impact wrench or socket wrench to loosen the bolt, or if necessary, a vice grip or hammer and chisel. If it is too stripped for those methods, you can try welding an additional bolt onto the blade. To avoid future issues, regularly clean the mower and apply anti-seize lubricant to the threads of the blade bolts when reinstalling.

You should have no problem removing a stuck lawn mower blade bolt with these tips.

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